You are going to HATE me for this, but you know what’s been going through my head all day today? Imagine this little ditty, if you will, sung to the tune of Rebecca Black’s “Friday”:

“It’s Pi Day, Pi Day, gotta eat pie on Pi Day, everybody’s looking forward to eating, eating. Eating pie, eating pie, yeah! Eating pie, eating pie, yeah! Yum yum yum yum, looking forward to eating pieeeee!”


You’re welcome.

Horrible earworms aside, isn’t Pi Day a fabulous idea? It takes a mundane day and a mathematical concept that holds absolutely no interest for me and somehow combines them to make a magical time where it’s appropriate—even encouraged!—to glutton out and feast on some mid-week pie. Yes please.


I actually made two pies for Pi Day, but I’ll be posting them separately for maximum Rebecca Black quoting opportunities. (Update: here’s the other one! Lime Coconut Pie) This first is a deep-dish Peanut Butter Pie. This baby has a chocolate cookie crust, a thin layer of whipped chocolate ganache, and a thick layer of peanut butter mousse. It’s topped with ganache, whipped cream, chopped peanuts, and peanut butter cups.


The whole thing was delicious, but the real star was the light, silky peanut butter layer. Traditional peanut butter pies are often made with Cool Whip (yuck) and cream cheese. We’re not big cheesecake lovers in this house, so I wanted to avoid creating anything that might resemble a peanut butter cheesecake. Instead, I used whipped cream and mascarpone cheese in the mousse, for a light, delicate texture that melts in the mouth.


Be warned that this pie is INTENSE. A small slice goes a long way! You could easily get 12-16 servings out of a 9” springform pan, so either invite all of your favorite friends over to feast on it, or be prepared to celebrate Pi Day all week long. Rebecca Black songs optional.

Peanut Butter Chocolate Pie
yield: one big beautiful 9-inch pie

Print This Recipe!

For the Chocolate Ganache:
8 ounces chopped semi-sweet chocolate
2/3 cup heavy cream
2 tbsp light corn syrup

For the Crust:
12 ounces Oreo cookies (about 26 cookies)
2 ounces (4 tablespoons) butter

For the Peanut Butter Mousse:
1 cup heavy cream
1 cup creamy peanut butter (not natural variety)
1 cup powdered sugar, sifted
1 teaspoon vanilla extract
1/2 teaspoon salt
8 ounces mascarpone cheese

To Garnish:
Whipped cream, chopped peanuts, extra ganache, peanut butter cups, etc

The ganache will need to cool for awhile, so it should be prepared first. Place the chopped chocolate in a heat-safe bowl, and combine the cream and corn syrup in a small saucepan over medium-high heat. Bring the cream to a boil, and as soon as it starts boiling, pour the hot cream over the chopped chocolate. Whisk everything together until the chocolate is melted and your ganache is shiny and smooth. Press a layer of cling wrap on top of the ganache.

The ganache now needs to cool until it’s the texture of peanut butter. You can leave it at room temperature, which will take several hours, or speed up the process by refrigerating it for 45-60 minutes.

While you wait for the ganache to cool, make the crust. Preheat the oven to 350 degrees Fahrenheit and spray a 9-inch springform pan with nonstick cooking spray. Place the cookies in a food processor and pulse in long bursts until they are in fine crumbs. Melt the butter and add it to the cookie crumbs, stirring until they’re evenly moistened.

Press the cookie crumbs in the bottom of the pan and up the sides about 2 inches. Bake the crust for 10 minutes, until it starts to puff and looks set but is not burned. Let it cool completely.

Once the ganache is thickened and the crust is cool, beat the ganache with a mixer until it is light, fluffy, and the texture of chocolate frosting. Spread it in the bottom of the cookie crust.

To make the peanut butter mousse, first whip the heavy cream until stiff peaks form, then transfer it to another bowl. In the same mixing bowl, combine the peanut butter and the powdered sugar and mix on medium speed until well-incorporated. (Mixture will be very stiff.) Add the vanilla extract, salt, and mascarpone cheese. Beat on medium speed until everything is well-combined. Mascarpone breaks easily, so don’t overwhip the mousse or leave the mixer running unattended.

Fold in 1/3 of the whipped cream to lighten the peanut butter mixture, then add the rest and gently fold everything together. Scrape the peanut butter mousse onto the whipped ganache, and spread everything into an even layer. Refrigerate the pie overnight, or for at least 6 hours until it is firm and set.

To finish it, garnish the top with whipped cream, chopped peanuts, chocolate peanut butter cups, or chocolate sauce. Store Peanut Butter Mousse in an airtight container in the refrigerator.


I’m linking this pie up at Crazy for Crust’s Pi Day Party!